Weekend

Most weeks the squad deals with villains. This week Phillips and Barratt are sent to unpick a marriage so strange that the neighbours noticed before the police did. The Issards, played by Derek Smith and Hilary Mason, have built a life together that makes no sense from the outside, and the two detectives have to work out whether the oddness is a crime or just a way of living. The case defies the usual categories, which is exactly why the episode works.

Hilary Mason is the kind of actress who knew her way around a British horror film, and she brings that weather to Mrs Issard. She can suggest volumes with a look, and the episode gives her plenty of looks. Derek Smith's Mr Issard matches her beat for beat, and together they give the episode its queasy, funny centre. Arthur Rowe's Mr Phillips completes the family picture, and Bernard Holley's Turnbull keeps the professional side of things ticking over.

Peter Hammond and Terence Feely wrote it, John Davies directed, and it went out on 21 January 1983. It is a small episode, closer to a play than a procedural, and it suits the two detectives well. Kevin O'Shea's Phillips and Paul Moriarty's Barratt are a good double act, and the show is smart to hand them the lead rather than keeping Maggie at the front of every story. It is a reminder that the show's regulars are actors first and uniforms second.

The title is a quiet joke about how the oddest arrangements are often the ones that survive. The truth of the Issards' marriage, when it comes, is stranger and sadder than anyone expected. No car chases, no guns; just people being odd in a very English way. And it is a strange, contained hour, and the series is more interesting for having made room for it.